TP53 mutations are evanescent and their VAF does not overtly increase with relapse. Out of 22 patients with serial specimens, 11 patients had at least 1 specimen with a pathogenic mutation. The VAFs for these mutations are shown in Figure 1B FL validation. To estimate changes in tumor cell content, we determined the sum of VAFs for mutations in a single amplicon of uBCL2 (solid black lines with orange blocks); this provides an estimate of the minimum tumor content. The TP53 mutations are depicted on the thick gray lines (red blocks mark the VAF; blue blocks denote that the mutation was not detected at that time point [for TP53] or only germ line sequence for uBCL2).